Police are appealing to the public for help in tracing two men seen acting suspiciously around the time of the fire and who fled the scene.

Lisa Livingstone, 40, her former partner Robbie Lehart, 50, and their young son Mikey, 6, managed to escape after a neighbour spotted the door ablaze and shouted to Lisa to get out.

Robbie is believed to have suffered serious burns after he opened an interior leading to the front door and was hit by flames.

'She opened the window and all she could see was the flames'

Lisa’s mother, Marie, 77, who lives nearby in Ffordd Dewi, said: “I was in bed. A man came down the street and he’s seen these two men hanging around by the door and saw the smoke. He was shouting: “Lisa! Lisa! Get out, there’s a fire.

A burnt door at Ffordd Las (Image: North Wales Police)

"She opened the window and all she could see was the flames. She grabbed Mikey and she’s ran out through the fire door in the back.”

Marie said Robbie was downstairs and Lisa shouted to him: “Quick, get out; there’s a fire.’

He’s opened the middle door and that’s when all the flames came from the front door.”

It took two hours to put out the flames

She said the fire service, police and ambulance rushed to the scene and they took Robbie to Ysbyty Glan Clwyd.

I took fire crews two hours to put out the flames.

Marie said her daughter was “upset and in a hell of a state.

“If it had been a bit later and nobody around . . . Luckily this man was there. He was shouting to her when she was in her bedroom. She was sleeping with the window open.

“Nobody can understand why it’s happened. There are just some bloody nutters around. I don’t think he’s from this town. We just have to wait for the police.”

The three-storey flat is next to the Premier Ffordd Las Store.

Its owner Nick Hyde said: "Police have come to see us to ask about a CCTV. A young family live there. It’s a bit of a mess isn’t it."

Two men fled the scene

North Wales Police Detective Inspector Chris Bell said: “We are carrying out a joint investigation with the North Wales Fire and Rescue Service and are treating this incident as arson.

“We are keen to trace two males seen acting suspiciously in the area and who fled the scene.”

A Wales Ambulance Service spokesman said: "An emergency ambulance attended the scene and a man was taken to Ysbyty Glan Clwyd with serious injuries."

A spokeswoman for the fire service said: "They used two sets of breathing apparatus, and one hose-reel jet to tackle the blaze.” The front door was 60% damaged with the front porch damaged by 35%."